Brown's office issued a statement condemning the federal judges decision and claimed the decision represents an unconstitutional intrusion by the federal government.

Without a U.S. Supreme Court reprieve, California will have to free roughly one-third of its prison inmates in a few years, and how that can be done safely is still hotly debated.

"The state has a number of options, including reform of the earned credit and parole systems, that would serve to reduce the population ... without adversely affecting public safety," the judges wrote in the decision.

The threat of recidivism by released inmates grabbed the attention of the sheriff's department, which is hatching a plan to deal with the inmates if they hit the streets.

The department declined to give details on the plan.

There is no set date for when the Ninth Circuit Court of Appeals will hear the case, said Scott Gerber, attorney general spokesman.